First brought to the US in 1784 for garden and street plantings, the Ailanthus altissima is sometimes referred to as the “Tree of Heaven,” based on its use in Chinese medicine. The Chinese name, chouchun, for Ailanthus translates as ‘foul smelling tree.’ It was soon discovered to spread rampantly through suckering, the sending up of shoots from the root system, and by its prolific seed production. It thrives in the temperate climate of our area, growing 3 to 6 feet in height per year to outcompete native tree species for sun, water and nutrients, while also suppressing competition with the allelopathic chemical, ailanthone. Its ability to thrive in poor soils, varying light conditions, and in drought, make it an invasive tree that is hard to control. It is difficult to eradicate, because when cut down, the roots send up shoots for many years.

Photo by Tom Anderson

Ailanthus leafs out in April in Frederick County. The compound, pointed, alternating leaves have smooth edges. Native trees with similar alternating leaves, like sumac and walnut, are easily distinguished, since the native trees have saw tooth edges. In June and July, female trees produce large clusters of seed.

In China, it is widely grown as a host for silkworms, and most parts of the tree have a use in Chinese herbal medicine. In Europe, Ailanthus spread rapidly immediately following World War II. It was able to take hold in rubble of cities where native trees could not thrive. The wood of the tree is not considered valuable for lumber, as its grain structure can vary considerably from early fast growth to later slower growth. However, in China, it is often used for charcoal, firewood, and for making steamers for cooking. Most often we see it as early tree growth in disturbed sites in our area.

A recent invasive insect, the Spotted Lanternfly (Lycorma delicatula,) was first detected in the United States in Berks County, Pennsylvania in September 2014. The Spotted Lanternfly is moving out into other areas, and, unfortunately, it can attack and kill a wide variety of trees, including domestic fruit trees, as well as other forest species. Preliminary studies show a relationship between the Spotted Lanternfly and Ailanthus as a host tree, and both the invasive insect and the tree originated in the same habitat in their native China. Since research is pointing to Ailanthus in helping this new invasive insect multiply, an additional reason is emerging for control of the invasive Ailanthus tree.

Article by Tom Anderson, FCFCDB member

Nature note for 5/5/2019